Diamond is among the most useful materials presently known, with hardness, thermal conductivity, and other properties that distinguish it from other materials. A diamond's hardness makes it well suited for use in cutting or grinding tools, such as use in saw blades, drill bits, or as an abrasive for polishing or grinding. Other uses for diamond include use in high-performance bearings, and in special purpose windows such as for aircraft mounted laser devices.
Diamonds are also well-known for their light dispersion and for their appearance, and are among the most desired elements used in creating jewelry. The scattering of light from a well-cut diamond distinguishes its appearance from other transparent or semitransparent crystals, making it visually more attractive. A diamond's hardness makes it resistant to scratching or other damage, making it among the most durable and practical jewelry materials for everyday wear.
Diamonds are also naturally insulators, but can be semiconductors when doped with certain impurities such as boron, which creates p-type diamond having a surplus of “holes”, or an absence of electrons, because boron has only three valence electrons which is one fewer than carbon. The thermal conductivity of diamond due to the strong covalent bonds with in the diamond structure also make it useful as a heat conductor, such as to conduct heat away from an integrated circuit or other semiconductor device.
But, diamond is difficult to find and is typically found in fairly small sizes in nature. Many of the applications described above illustrate potential uses for large, high-quality diamonds, were such diamonds to become commercially available. Larger jewels, larger semiconductor substrates, larger windows, and larger diamond elements on cutting tools are all desirable, and illustrate the need for large diamonds.